Thermal electric cut-out.



PATBNTED JAN'. 20, 1903.

T. E. SGANTLTN. V THERMAL ELECTRIC GUT-OUT.

APPLICATION FILED SEPT. 5, 1901.

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UNTTED ySTATES ATENT OFFICE.

THOMAS E. SCANTLIN, OF LAFAYETTE, INDIANA.

THERMAL ELECTRIC CUT-OUT..

SPECIFICATION forming' part of Letters Patent No. 718,660, dated January20, 1903 Application tiled September 5, 1901. 'Serial No. 74,411- (Nomodel.)

To all whom, t may concern,.-

Beit known that I, THOMAS E. SoAN'rLlN, a citizen of the United States,residing at Lafayette, in the county of Tippecanoe and State of Indiana,have invented certain new and usefullmprovementsinThermalElectricCut-Outs; and I do declare the following to be a full, clear, and exactdescription of the invention, such as will enable others skilled in theart to which it appertains to make and use the same.

This invention relates to a thermal electric cut-out primarily designedfor protecting telephone and telegraph instruments and equipments fromsneak currents of higher potentiality or amperage than suchinstrumentsand equipments are designed to withstand, but capable also ot' beingemployed effectuallyT as a current-arrester in electric circuits andconnections of all kinds where protection from abnormal currents is ormay be found necessary or desirable.

The object of the invention is to provide a thermal cut-out which issimple of construction, inexpensive of production, and quick-acting.

Vith this and other objects in view, which will appear as the nature ofthe improvements is better understood, the invention consists of certainnovel features of construction, combination, and arrangement of parts,as will be hereinafter more fully described, and particularly pointedout in the appended claims.

In the accompanying drawings, Figure 1 is a perspective view of acut-out embodyingmy invention. Fig. 2 is a longitudinal section of thesame. Figs. 3, 4, 4a, 5, 6, 7, and 8 are views similar to Fig. 2,showing modiiied forms of the cut-out; and Fig. 9 is a view showing theapplication of the invention to its supports.

Referring now more particularly to Figs. l and 2 of the drawings, theletters a b indicate the terminals of the cut-out, and c itsnon-conducting casing or receptacle. The terminal ct has projectingtherefrom a pin d, which enters the bore of a tube e, carried by theterminal b. The outer end of this tube has a threaded stem f, which iitswithin a threaded socket in a non-conducting bushing g, occupying theopening in the said terminal b, which is of ring form. The pin d isconnected with the tube e by the fusible connection h, composed ofsolder or some other fusible material which will melt at a relativelylow degree of heat. The terminals a and b close the ends of thereceptacle c, and one or both of them may have an endwiseslidingmovement to withdraw the pin and tube from engagement when released bythe melting of the said fusible connection. The space or chamber betweenthe pin and tube and the wall of the receptacle contains a tilling ofsubdivided or aggregated resistance material z', which preferablyconsists of carbon, German silver, or some other suitable material oflow conductivity and high resistance, said material being ofpulverulent, powdered, or granular form in order to secure the bestresults. This material is in electrical connection with the terminals ctb, and when an abnormal current passes through the cut-out or arresterthe resistance material becomes heated, and as the heat therefrom istransmitted to the pin and tube the solder or fusible connection betweenthem is melted, leaving them free toY be withdrawn from engagement witheach other by an endwise-sliding movement of one or both, as desired.The outer surface of the tube e is covered with a layer j of waxedpaper, silk, or other suitable insulating material for the purposeofdecreasing the exposed conducting-surface Yot' said tube to cause thecurrent to pass through the resistance material throughout the length ofthe receptacle, thereby increasing the resistance and producing a higherdegree of heat. This result is also promoted by the use ot thenon-conducting bushing g and utilizing the resistance medium forelectrically connectingthe two terminals, as shown. In the presentinstance I have shown the terminal b as adapted to be moved to withdrawthe pin from engagement with the tube, which is effected by meansherein- IOO pin and tube are connected as before by the fusibleconnection 7L', and the resistance material t envelopsV the same and isconfined in l the casing c and electrically connects the terminals a.and Z9.

In the construction shown in Fig. -lt the two terminals t2 b2 are unitedby the fusible connection h2 with metallic cups or caps 7.3, which closethe ends of the receptacle c2 and are fixed thereto in any desiredmanner. The resistance material i2 contained in said receptacleelectrically connects the two terminals 0,3 b2 through the metallic caps7c. When the resistance material is heated by the passage of an abnormalcurrent, the heat is transmitted to the caps la and thence to thesolder, which is melted and releases the terminals from said caps. Ifdesired, however, the caps r may be fixed to or formed integrally withthe terminals and releasably connected by fusible material h3, such asshellac or solder, to the ends of the receptacle, as shown in Fig. 4, soas to be disengaged therefrom with the terminals when the shellac orsolder is melted.

In the construction shown in Fig. 5 the two caps r/ are united by thefusible connection 7L4 and are fixed to the inner ends ofthe sections 03c4 of a two-part casing or socket, each section containing a filling ofresistance material 3, and the outer ends of said sections are formedwith threaded sockets m for the reception of screw-threaded stems n, onthe terminals a3 ZF. By this construction the terminals are electricallyconnected by the resistance material, caps, and threaded stems, as willbe readily understood. The heating of the resistance material and capscauses the fusible connection 7L to melt and release the two parts ofthe cut-out from engagement in an Obvious manner.

In the construction shown in Fig. 6 the caps t2 are fixed to the ends ofthe receptacle, as in Fig. 4L, and have conical sockets o, which projectinto said receptacle and receive conical projections p on the terminalsa4 b4, the said conical sockets and projections being united by thefusible connection h5. The electrical connection between the twoterminals is here made through the resistance material and the conicalmembers. The operation of the device as thus constructed Will be readilyunderstood from the foregoing description.

In the construction shown in Fig. 7 both the pin d5 and the tube e5 areinsulated from the terminals d5 D5. The pin d5 is provided with ascrew-threaded end d, which screws into the non-conducting bushing g5,which in turn is threaded into the terminal a5. The tube e5 is similarlyprovided `with a threaded stem e6, which fits within a threaded socketin the non-conducting bushing c7, which is screw-threaded into the endof the terminal b5. The pin fits within the tube e5, as in theconstruction shown in Fig. 2, and is held in place by solder or otherfusible material.

The space between the tube e5 and the nonconducting' receptacle orcasing c5 is filled with the resistance material or substance In theconstruction shown in Fig. 8 I do away with the receptacle or casing andunite the two terminals a6 b by an admixture of the subdivided oraggregated substance or material t, which is a conductor, with somesuitable material such as shellac,rosin,glue, or waxwhich will bind theparts of the subdivided material together` and unite the terminals d6h6. Upon the passage of an abnormal current through the terminals thisadmiXture will fuse or melt, and the terminals will thereupon separate,as will be readily understood.

Fig. 9 of the drawings shows one mode of mounting the cut-out andwithdrawing the terminals for engagement upon the melting of the fusibleconnection, the withdrawal of one or both terminals from their normalposition being deemed preferable to arrest the passage of any current,although the parts may be so disposed or constructed as to effect thepositive cut-olf of the current in any other desired way. In Fig. 9 twoconducting and supporting plates q q are mounted upon a suitable base Rand are designed to be con- Vnected up in the telephone or telegraph orother circuit in any approved manner.

Each of these plates is slotted or formed with an open bearing at itsupper end, as shown at s, to receive the coperating terminal a or b,which is grooved at 3 to receive the walls of said slot, whereby thecut-out, which extends longitudinally between the plates, is held fromendwise movement. A spring det-ent t is also formed on each plate tobear upon the terminal and hold the same securely seated in the slot.The free end of the plate q,Wl1ich is of spring metal, is bent out ofits normal position to engage the terminal b and is held under springtension, so that when the fusible connection 77. is melted said springby its retractile force will pull the terminal b outwardly, therebywithdrawing the terminals from engagement with each other. Either one orboth of the terminals may be mounted in this or any equivalent manner,as desired, and the movable spring-plates upon resuming their normalposition may be made to contact with a ground connection, thus throwingthe current to the earth until the parts are again restored foroperation.

It will be seen from the foregoing description that each embodiment ofthe invention herein disclosed consists of terminals separable by theaction of heat and a resistance medium consisting of a subdividedmaterial formed of aggregated parts, which on becoming heated effectsthe disconnection of the terminals, thereby cutting off the flow of thecurrent. The specific kind or character of the subdivided materialemployed is immaterial so long as it is of sufficiently low conductivityto perform this function.

The resistance material may be made of IIO any desired subdividedsubstance or substances of low conductivity and high resistance. The useof carbon or German silver in granular form is preferred; but I havealso secured good results from the use of a good conducting material ingranular form admixed with a non-conducting material-such as shellac,rosin, glue, cement, or waX-so that the former shall be wholly orpartially enveloped in the latter, the current passing from one grain orparticle to another and arcing through the non-conducting envelop, thusexciting energy and increasing the resistance and production of heat.

It is to be understood that by the use of the terms subdividedresistance, granular resistance, resistance medium of aggregated parts,dac., I mean any resistance medium composed of combined parts orparticles eitherloosely confined or bound together by a suitable cementand through which an electric current may pass by a step-by-stepmovement, as by jumping from one part or particle to another.

As an instance, as heretofore stated, I may use carbon or German silverin granular or powdered form or any other material of like lowconductivity and high resistance. I disclaim the use of aggregated coilsof resistancewire, as a multiple conductor formed of two or more coilswould lessen the resistance to an objectionable degree and alsomaterially increase the cost of construction.

The invention may be employed in electrical equipment of all kinds wherethe use of a current-arrester is required.

Having thus described my invention, what I claim as new, and desire tosecu re by Letters Patent, is

I. An electric-current cut-out consisting of two separable bodies, aneasily-fusible cement uniting the same, and a resistance medium ofaggregated parts adapted to be heated by an abnormal current to fusesaid cement and forming a broken or interrupted electrical connection oflow conductivity between said bodies through which a current passes byjumping from part to part, substantially described.

2. An electric cut-out having terminals separable by the action of heat,and a resistance medium of aggregated parts adapted to be heated by anabnormal current to effect the separation, substantially as specified.

3. An electric-current cut-out consisting of an envelop having terminalsseparable by the action of heat and containing a loose granularresist-ance medium adapted to be heated by an abnormal current to effectthe separation, substantially in the manner'specied.

t. An electric-current cut-out consisting of a receptacle, terminals, afusible connection between the terminals, and a granular filler ofresistance material within said receptacle to fuse said connection,substantially as set forth.

5. An electric-current cut-out consisting of a receptacle, terminalsclosing the ends of the receptacle, a fusible connection between theterminals, and a granular iller of a resistance material confined by theterminals Within said receptacle and adapted to fuse said connection,substantially as described.

6. An electric-current cut-out consisting of anon-conducting casing,twoseparable bodies, an easily-fusible cement uniting the separable bodies,and a filler of granular resistance material within the casing forfusing the cement to separate said bodies, substantially as set forth.

7. An electric-current cut-out consisting of a non-conducting casing,terminals closing the ends of the casing, a two-part separableconnection between the terminals, one of said parts being insulated fromits terminal, an easily-fusible cement uniting the parts of theseparable connection, and a filler of a resistance material ofaggregated parts within the casing, said iiller connecting the terminalsand being insulated from one of the said parts of the separableconnection, substantially as specified.

In testimony whereof I have hereunto set my hand in presence of twosubscribing witnesses.

THOMAS E. SCANTLIN.

